Download presentation
Presentation is loading. Please wait.
Published byMiles Rogers Modified over 8 years ago
1
Chemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors in which they take place. Lecture 10
2
Today’s lecture Definition of Selectivety Instantaneous S D / U = r D /r U Overall = F D /F U Semibatch Reactors 2
3
Selectivity in Multiple Reactions SelectivityYield Instantaneous S D/U = r D /r U Overall Ŝ D/U = F D /F U 3 Keep C A high and C B low.
4
Semibatch reactors Semi Batch reactors can be very effective in maximizing selectivity in liquid phase reactions. The reactant that starts in the reactor is always the limiting reactant. 4
5
Semibatch reactors A + B → C + D Semibatch reactors 5 A B, v 0 Initial V Liquid level and volume increase
6
Semibatch reactors 6 Mass Balance:
7
Semibatch 7 1)Mole balances: Species A: in – out + gen = acc
8
Semibatch 8 1)Mole balances: Species B:
9
Semibatch 9
10
2) Rate Law: 3) Stoichiometry: 4) Parameters: 10
11
example: A + B → C + D + CO 2 A B, v 0 CO 2 Semibatch Example 1a) Mole balances: 11
12
1 b) Mass balances: Semibatch Example 2) Rate Law: 12
13
3) Stoich: Semibatch Example 4) Parameters: 13
14
Polymath Screenshots: 14
15
Semi Batch Reactors Three Forms of the Mole Balance applied to Semi Batch Reactors: 1.Molar Basis 2.Concentration Basis 3.Conversion 15
16
Consider the following elementary reaction: A+B C+D -r A =kC A C B The combined Mole Balance, Rate Law, and Stoichiometry may be written in terms of number of moles, conversion, and/or concentration: ConversionConcentrationNo. of Moles 16
17
Polymath Equations: 17
18
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions Everything is the same as for the irreversible case, except for the rate law: Consider the following reaction: A+B C+D 18
19
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions Where: At equilibrium, then 19 X e changes with time.
20
End of Lecture 10 20
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.